This invention is a switching device comprising a cell which includes a structure capable of moving back and forth between two end positions and actuating electrodes to subject the structure to attraction forces to control its movement.
Devices of this type are used, in particular, to influence or interrupt the trajectory of optical beams in systems which control, process and store information on pixel-based images. One particularly interesting application for these systems is for printing or high definition reproduction systems.
French patent FR 2 726 135 describes one such device, made in the form of a micro-mechanical structure, and an installation for optical switching using several devices placed in an array.
This invention aims to improve the reliability, durability and performance of the above-mentioned device. In particular, the aim of the invention is to provide a switching device where the cell is equipped with a moving structure which moves in a regular way in a single plane, does not rebound when it reaches its end positions and where there is little risk of remaining stuck to the electrodes.
In order to achieve these goals, the switching device according to the invention is characterised by the actuating electrodes of its cell being positioned on both sides of the moving structure, in such a way as to follow the exact shape of said moving structure when it is at either of its two end positions.
This device also benefits from one or several of the main characteristics listed below.
The moving structure is formed by a flexible cantilever beam and a screening blade integrally connected to the beam. In this case, the electrodes are only located on each side of the beam.
Adjacent to each electrode there is at least one stopper serving as a stop for the beam and intended to prevent it from coming into contact with the electrode. This stopper is, for instance, located at the free end of the cantilever beam, beyond the screen. Furthermore, it is preferable to provide for several stoppers distributed along the whole length of the electrodes.
The side walls of the moving structure, stoppers and electrodes are coated with a layer of diamond, preferably made to act as a conductor, or any material with the same properties.
The switching device is made on a substrate which has a transverse aperture positioned in such a way as to be closed by the screen when the system is in one of its end positions. This aperture has, on the substrate""s side opposite the screen, one portion with a greater diameter than its portion located on the side of the screen. It is preferable if this portion is conical.
The beam has either a xe2x80x98Txe2x80x99 shaped cross-section or any other shaped cross-section able to enhance its out-of-plane rigidity.
Each electrode connected to a conductor is connected to a control circuit; the connection of the electrode to this conductor may comprise an incorporated fuse.